1. Field of the Invention
The invention relates to shaping a leather skin which is intended to be incorporated in a trim component, in particular of the type which comprises a rigid support which delimits a cavity, a leather skin, one edge of which is applied against a rigid support in the cavity, and a foam which is arranged between the rigid support and the leather skin.
2. Description of Related Art
Components of the above-mentioned type having skins of plastics material are commonly used for various automotive trims, in particular for dashboards and door trims. Substantially for reasons of aesthetics, it is desirable to use leather as the skin. However, this presents a given number of problems because it is constituted by a natural material which has variations in properties and it is therefore necessary to carry out specific treatments.
In the case of the above-mentioned components, examples of which are illustrated in the drawings of FIGS. 1 and 2, a rigid support 10 which is generally formed by a thermoplastic material retains a skin 12 at the edge 14 thereof, and a foam 16 is arranged between the support 10 and the leather skin 12. In a developed method, the pressure of the foam 16 injected between the rigid support and the skin is what presses the edge 14 of the leather against the support 10 and ensures sealing.
In the case of skins of plastics material, it is known to determine conditions such that the foam does not tend to become introduced between the skin and the support. However, in the case of leather whose properties may vary from one piece to the next, it is necessary to provide for operations which always ensure good sealing between the edge of the skin, more specifically the outer surface 18 thereof which is generally the grain, and the rigid support.
It has been suggested, in order to improve the flexibility of the edge of the skin and therefore to obtain better sealing, to apply to the edge of the leather skin a paring operation, that is to say, an inclined incision of the edge whose thickness thereby decreases progressively towards the edge, as indicated by the reference 20 in FIG. 2. However, this solution is not always sufficient, in particular when the leather is not very pliable.
When such a trim component is observed, it is possible to distinguish three regions in the leather skin, a sealing region A in which the outer face of the skin must be pressed against the rigid support, ensuring the sealing with respect to the injected foam whilst allowing air to be discharged from the cavity, a region B in which the skin has a change in direction, and a region C in which the skin is practically in continuation of an outer surface of the rigid component which surrounds it.
Owing to variations in the properties of leather from one piece to the next, the region B may have variable properties so that good sealing is not always provided and the foam can appear between the skin and the rigid support.
Document EP-145 560 describes a method for shaping leather in the region of a sole of a shoe. Document WO2004/097053 relates to a method for finishing leather objects by localised processing of the edges only. Document GB-1 027 801 describes an operation for processing leather by means of water or water vapour applied only to regions of leather components. Document DE-19 926 470 describes the application of protective layers to the inner face of a decorative coating, in which the portions which must not be shaped are made rigid.
None of these documents allows the problem addressed to be solved by managing the shape of a leather skin beside a fluid-tight cooperation region between a leather skin and a rigid support by means of simple pressure, and more specifically managing the portion of skin in the region B so that the fluid-tight cooperation conditions in the region A are optimised.
The invention relates to a solution to this problem addressed, by varying the sealing between a leather skin and the rigid support.